Study Of The Carbonation Resistance Of Concrete With Nano-modified Waterborne Coating

Under general atmospheric conditions,concrete carbonation is the main reason for the failure of reinforced concrete structure,causing huge economic losses.Organic Coatings is the most convenient and effective protection means for the carbonation protection of concrete in service.The Coatings protection mainly use the traditional organic solvent Coatings,in the process of production,use will send a large number of harmful organic compounds,safety,environmental problems,and waterborne Coatings will not send toxic organic compounds,has the advantage of safety and environmental protection,but the physical properties of waterborne Coatings and aging resistance is generally inferior to the traditional organic solvent Coatings.This thesis adopts two kinds of nano materials,two kinds of dispersion for different waterborne Coatings nano modification,through UV radiation accelerated aging,natural aging and accelerated carbonation test on waterborne Coatings concrete aging before and after the carbonation resistance of research,and aging Coatings microstructure and chemical composition analysis through the scanning electron microscope and Fourier infrared spectrum analyzer.Analyze the improvement effect and improvement mechanism of nanomaterials on the carbonation and aging resistance of waterborne Coatings from both quantitative and qualitative aspects.The main achievements achieved are as follows:1.The improvement effect of unmodified nanomaterials on the carbonation resistance of waterborne Coatings is better than that of hydro-modified nanomaterials.Contrary to the conclusion in organic solvent-based Coatings,the unmodified nanomaterials can be more closely combined with waterborne Coatings,and the hydration modification reduces the optimal incorporation of nanomaterials in waterborne Coatings.The optimal incorporation of unmodified nanomaterials in waterborne Coatings is 2 to 3 percent,and the optimal incorporation of unmodified nanomaterials in waterborne Coatings is 1 to 2 percent.The carbonation and aging resistance of unmodified nanomaterials is better than that of hydro-modified nanomaterials.2.Compared with nano-Si O₂,nano-Ti O₂ can effectively improve the long-term carbonation resistance of the waterborne Coatings.Before the Coatings aging,the improvement of the carbonation resistance of different nanoparticles to the Coatings is not very different.After the Coatings aging,the improvement of the carbonation resistance of the nano-Ti O₂ to the waterborne Coatings is significantly greater than that of the nano-Si O₂.After Coatings aging,the carbonation resistance of the unmodified nano-Ti O₂ coated concrete is increased by about 20%compared with the unmodified nano-Si O₂incorporation.3.Through theoretical analysis and regression analysis of test data,the prediction model of Carbonation depth of waterborne coated concrete and carbonation resistance Life of waterborne Coatings are established.While the predicted service life of waterborne epoxy resin and waterborne polyurethane without nanomaterials is 2.8 years and 1.9 years respectively,the unmodified nano Ti O₂ can increase the service life of waterborne epoxy resin Coatings by 67.5%to 4.69 years;and the service life of waterborne polyurethane by 37.17%to 2.62 years.The accelerated carbonation process of waterborne coated concrete is simulated by the finite element software COMSOL,and the prediction model of carbonation depth and the calculation formula of the diffusion coefficient of CO₂ in the waterborne Coatings are verified,and the simulation error of concrete for long-term carbonation is less than 10%.There are 55 figures,29 tables and 118 references in this thesis.